which puzzles us."
"In what way?"
"Well, suppose the instinct works on some physical basis--for instance, smell. If there were anything in recent juxtaposition to the attacked which would carry the scent, surely that would supply the missing cause."
"Of course!" Adam spoke with conviction.
"Now, from what you tell me, the negro had just come from the direction of Diana's Grove, carrying the dead snakes which the mongoose had killed the previous morning. Might not the scent have been carried that way?"
"Of course it might, and probably was. I never thought of that. Is there any possible way of guessing approximately how long a scent will remain? You see, this is a natural scent, and may derive from a place where it has been effective for thousands of years. Then, does a scent of any kind carry with it any form or quality of another kind, either good or evil? I ask you because one ancient name of the house lived in by the lady who was attacked by the mongoose was 'The Lair of the White Worm.' If any of these things be so, our difficulties have multiplied indefinitely. They may even change in kind. We may get into moral entanglements; before we know it, we may be in the midst of a struggle between good and evil."
Sir Nathaniel smiled gravely.
"With regard to the first question--so far as I know, there are no fixed periods for which a scent may be active--I think we may take it that that period does not run into thousands of years. As to whether any moral change accompanies a physical one, I can only say that I have met no proof of the fact. At the same time, we must remember that 'good' and 'evil' are terms so wide as to take in the whole scheme of creation, and all that is implied by them and by their mutual action and reaction. Generally, I would say that in the scheme of a First Cause anything is possible. So long as the inherent forces or tendencies of any one thing are veiled from us we must expect mystery."
"There is one other question on which I should like to ask your opinion. Suppose that there are any permanent forces appertaining to the past, what we may call 'survivals,' do these belong to good as well as to evil? For instance, if the scent of the primaeval monster can so remain in proportion to the original strength, can the same be true of things of good import?"
Sir Nathaniel thought for a while before he answered.
"We must be careful not to confuse the physical and the moral. I can see that already you have switched on the moral entirely, so perhaps we had better follow it up first. On the side of the moral, we have certain justification for belief in the utterances of revealed religion. For instance, 'the effectual fervent prayer of a righteous man availeth much' is altogether for good. We have nothing of a similar kind on the side of evil. But if we accept this dictum we need have no more fear of 'mysteries': these become thenceforth merely obstacles."
Adam suddenly changed to another phase of the subject.
"And now, sir, may I turn for a few minutes to purely practical things, or rather to matters of historical fact?"
Sir Nathaniel bowed acquiescence.
"We have already spoken of the history, so far as it is known, of some of the places round us--'Castra Regis,' 'Diana's Grove,' and 'The Lair of the White Worm.' I would like to ask if there is anything not necessarily of evil import about any of the places?"
"Which?" asked Sir Nathaniel shrewdly.
"Well, for instance, this house and Mercy Farm?"
"Here we turn," said Sir Nathaniel, "to the other side, the light side of things. Let us take Mercy Farm first. When Augustine was sent by Pope Gregory to Christianise England, in the time of the Romans, he was received and protected by Ethelbert, King of Kent, whose wife, daughter of Charibert, King of Paris, was a Christian, and did much for Augustine. She founded a nunnery in memory of Columba, which was named SEDES MISERICORDIOE, the House of Mercy, and, as the region was Mercian, the two names became involved. As Columba is the Latin for dove, the dove became a sort of signification of the nunnery. She seized on the idea and made the newly-founded nunnery a house of doves. Someone sent her a freshly- discovered dove, a sort of carrier, but which had in the